Spark plug



June 15,1926. 1,588,489

A. R. MOSLER SPARK PLUG Filed Jan. 30 1925 INVENTOR M ATTORNEYS Patented June 15, 1926.

UNITED STATES ABJIHUR R. MOSLER, OF NEW YORK, N. Y.

SPARK PLUG.

application filed January 30, 1925. Serial No. 5,755.

' The object of my invention is to produce a spark plug in which novel means are employed for ensuring a gas tight joint and in which other novel features are incorporated, as will hereinafter appear.

Practical embodiments of my invention are represented in the accompanying drawings, in which Fig. 1 represents one tudinal central section.

Fig. 2 represents another embodiment partly in side elevation and partly in longitudinal central section.

Fig. 3 represents an end view of the sleeve of compressible material.

Fig. 4 represents a side view of the-same partly in section.

- ig. 5 represents an outer end View of the tubular wedge.

Fig. 6 represents a side View of the same partly in section.

In the embodiment shown in Fig. 1, the spark plug shell 1 has an exteriorly screwthreaded inner end 2. The bore of the shell has an outer flaring portion 3 (in the present instance an outwardly flaring portion) and an inner cylindrical portion 4, the base of the flaring portion 3 having an annular shoulder 5 and the base of the cylindrical portion 4 having an annular shoulder 6. The shank 7 of the center spindle has a screw-threaded outer end 8 for the reception of the terminal nut 9. A head 10 is provided at the inner end of the shank 7,

orming an annular shoulder 11 facing the annular shoulder 6. This head 10 of the center spindle has an axial hole 12 into which is driven the center electrode 13. The shell 1 is provided with an electrode 14 projecting diagonally into the proper spaced relationship to the center electrode 13.

A tube 15 of suitable insulating material, such as wrapped mica, surrounds the shank 7 v of the spindle and extends from the shoulder 11 of the head 10 to the screwthreaded outer end 8 of the spindle shank.

A mass of insulating material such, for instance, as a plurality of superposed mica washers 16 surrounds the insulating tube 15 and is longitudinally compressed between the shoulder 6 of the shell and the shoulder 11 of the spindle head, the exterior of which mass may be transversely corrugated to form an extended exposed surface for the mass.

Another mass of insulating material 17 embodiment in longisurrounds the insulating tube 15 between the outer end of the shell 1 and the terminal nut 9, suitable washers being inserted between the ends of the mass 17 and the shell and nut respectively.

The means which I employ for ensuring a gas tight joint between the shell and spindle is as follows:

A sleeve 18 of compressible material, as brass, for instance, surrounds the insulating tube 15 within the outwardly flaring bore portion 3 of the shell. A tubular wedge 19 of metal such, for instance, as soft steel, surrounds the sleeve 18, the inner and outer walls of said tubular wedge fitting the sleeve 18 and the outwardly flaring bore portion of the shell respectively. The ends of the sleeve 18 project beyond the ends of the tubular wedge 19 and are spread by the action of the wedge as it is forced inwardly along the bore portion 3 of the shell to compressthe sleeve and thereby the insulating tube 15, to form a gas tight joint. The shoulder 5 at the smaller end of the bore portion 3 serves to limit the inward movement of the sleeve 18 as the tubular wedge is forced inwardly to compress the sleeve.

In the modified form shown in Fig. 2, the center spindle 20 projects inwardly beyond the inner end of the shell 21 and a mass of insulating material 22 surrounds the insulating tube 23 between the inner end of the shell and the center electrode disc 24 which is inserted between the said insulating mass 22 and the head 25 of the center spindle. An electrode 26 projects from the inner end of the shell 21 through the insulating mass 22 into position to coact with the center disc electrode 24. In this form the bore of the shell 21 is provided with an outwardly flaring portion 27 in which is located the sleeve 28- of compressible material such, for instance, as brass and the tubular wedge 29. The outer end of the shell 21 is provided with a recess 30 in which the inner end of a mass of insulating material 31 is housed, suitable washers being interposed between the inner and outer ends of the insulating mass 31 and the shell 21 and terminal nut 32 respectively.

For locking the Wedge to the shell, the shell is preferably provided with a shallow recess 33 near the outer end of its flaring bore portion 27, into which shallow recess a portion of the wedge is spread when the wedge is forced longitudinally into position, to form the gas tight joint.

In both of these embodiments hereinabove described, it will be seen that a very simple and eii ective device is provided for locking the spindle in the shell with a gas tight joint, the use of the sleeve of compressible material between the tubular wedge and the insulating tube effectually protecting the tube from damage when the wedge is forced injovardly to compress the sleeve around the tu e.

It is evident that various changes may be resorted to in the construction, form and arrangement of the several parts without departing from the spirit and scope of my invention; hence, I do not intend to be limited to the particular embodimentsherein shown and described, but

What I claim is 1. In a spark plug, a shell, the bore of which has an outwardly flaring portion, a tubular wedge therein, a center spindle, an insulating tube thereon, additional insulating means cooperating with said spindle and said shell to secure the former against dislocation in an outward direction with respect to the latter, and a sleeve of compressible material compressed between said wedge and tube to make a gas tight joint.

2. In a spark plug, a shell, the bore of which has a flaring portion, a tubular wed e therein, a center spindle, an insulating tu e thereon, and a sleeve of compressible material compressed between said wedge and tube to make a gas tight joint, the ends of the sleeve being spread beyond the ends of the wedge by the compression action of the wedge.

3. In a spark plug, a shell, the bore of which has an outwardly flaring portion, a tubular wedge therein, a center spindle, an

insulating tube thereon, additional insulating means cooperating with said spindle and said shell to secure the former against dislocation in an outward direction with respect to the latter, and a sleeve of compressible material compressed between said wedge and tube to make a gas tight joint, the ends of the sleeve being spread beyond Leeaaee the ends of the wedge by the compression action of the wedge.

4. In a spark plug, a shell, the bore of which has a flaring portion, a tubular wedge therein, a center spindle, an insulating tube thereon, and a sleeve of compressible material compressed between said wedge and tube to make a gas tight joint, the ends of the sleeve being spread beyond the ends of the wedge by the compression action of the wedge, a shoulder being provided at the smaller end of said flaring portion of the bore for limiting the endwise movement of the sleeve.

5. In a spark plug, a shell, the bore of which has an outwardly flaring portion, a tubular wedge therein, a center spindle, an insulating tube thereon, additional insulating means cooperating with said spindle and said shell to secure the former against dislocation in an outward direction with respect to the latter, and a sleeve of compressible material compressed between said wedge and tube to make a gas tight joint, the ends of the sleeve being spread beyond the ends of the wedge by the compression action of the wedge, a shoulder being provided at the smaller end of said outwardly flaring portion of the bore for limiting the endwise movement of the sleeve.

6. In a spark plug, a shell, the bore of which has an outwardly flaring portion, a tubular wedge therein, a center spindle, an insulating tube thereon, an insulating mass around each end of said insulating tube, a sleeve of compressible material around said tube intermediate said insulating masses and compressed between said tubular wedge and said tube to make a gas tight joint, the ends of the sleeve being spread beyond the ends of the wedge by the compression action of said wedge, a shoulder being provided at the smaller end of said outwardly flaring portion of the bore for limiting the endwise movement of the sleeve.

In testimony that I claim the foregoing as my invention, I have signed my name this 19th day of December, 1924:.

ARTHUR R. MOSLER. 

